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Biomedical subjects

N Tonami

Publications and source records attributed to N Tonami.

At least 289 records · Page 16Linked to original sources
PubMed1984

Quantification of segmental wall motion by length-based Fourier analysis.

A new method for evaluating segmental wall motion by length-based Fourier analysis is described. Fourier analysis is performed on a series of lengths from a center to edges of the ventricle, generating parameters of percent length shortening (%LS) and phase of the segment (length-based phase). The reproducibility of the result was good, since the algorithm was automatic except for the setting of the ventricular region as a mask image to exclude surrounding blood pools. This program can be applied for quantification of ventricular wall-motion abnormalities in gated blood-pool studies, and for analysis of the timing of ventricular contraction in gated blood-pool emission computed tomography to detect the site of an accessory conduction pathway in patients with Wolff-Parkinson-White syndrome.

Arrhythmias, Cardiac↗
PubMed1984

Phase analysis in the Wolff-Parkinson-White syndrome with surgically proven accessory conduction pathways: concise communication.

Twenty-one patients with the Wolff-Parkinson-White (WPW) syndrome who underwent surgical division of the accessory conduction pathway (ACP) were studied by gated blood-pool scintigraphy. In each case, a functional image of the phase was generated, based on the fundamental frequency of the Fourier transform. The location of the ACP was confirmed by electrophysiologic study, epicardial mapping, and surgery. Phase analysis identified the side of preexcitation correctly in 16 out of 20 patients with WPW syndrome with a delta wave. All patients with right-cardiac type (N = 9) had initial contraction in the right ventricle (RV). In patients with left-cardiac type (N = 10), six had initial movement in the left ventricle (LV); but in the other four the ACPs in the anterior or lateral wall of the left ventricle (LV) could not be detected. In patients with multiple ACPs (N = 2), one right-cardiac type had initial contraction in the RV, while in the other (with an intermittent WPW syndrome) the ACP was not detected. These observations indicate that abnormal wall motion is associated with the conduction anomalies of the WPW syndrome. We conclude that phase analysis can correctly identify the side of initial contraction in the WPW syndrome before and after surgery. However, as a method of pre-operative study, it seems difficult to determine the precise site of the ACP by phase analysis alone.

Adolescent↗
PubMed1983

Emergency blood pool scintigraphy in fresh-blood-aspirated focal liver disease.

Emergency blood pool scintigraphy was performed in a patient clinically diagnosed as having a liver abscess, in whom percutaneous drainage revealed that the lesion containing fresh blood. 99mTc-RBC images 18 h after the injection showed only patchy activity in the lesion, therefore, we considered there was no communication between the lesion and the circulating blood. Drainage of the lesion was performed again and the abscess with a blood clot was drained.

Adult↗
PubMed1982

Deferoxamine mesylate enhancement of 67Ga tumor-to-blood ratios and tumor imaging.

To improve the tumor-to-blood ratio in 67Ga tumor imaging, the effect of administration of deferoxamine mesylate (DFO) was evaluated. DFO improved 67Ga tumor-to-blood ratios in tumor-bearing rats. Administration of DFO 12 h after 67Ga injection did not decrease the concentration of radioactivity in the tumor of rats, but administration of DFO 4 h after 67Ga decreased the concentration of radioactivity in the tumor. Serum unsaturated iron binding capacity in rats was transiently increased by DFO administration, but when DFO was administered before 67Ga injection the tumor uptake showed rather decreased levels. In human studies, DFO accelerated the excretion of 67Ga from the blood, but tumor images were not necessarily improved.

Animals↗
PubMed1982

A noninvasive method for evaluating portal circulation by administration of Ti-201 per rectum.

A new method for evaluating portal systemic circulation by administration of TI-201 per rectum was performed in 13 control subjects and in 65 patients with various liver diseases. In normal controls, the liver was visualized on the 0--5-min image whereas the images of other organs such as the heart, spleen, and lungs were very poor. In patients with liver cirrhosis associated with portal-systemic shunt, and in many other patients with hepatocellular damage, the liver was not so clearly visualized, whereas radioactivity in other organs, especially the heart, became evident. The heart-to-liver uptake ratio at 20 min after administration (H/L ratio) was significantly higher in liver cirrhosis than in normals and patients with chronic hepatitis (p less than 0.001). The patients with esophageal varices showed a significantly higher H/L ratio compared with that in cirrhotic patients without esophageal varices (p less than 0.001). The H/L ratio also showed a significant difference (p less than 0.01) between Stage 1 and Stage 3 esophageal varices. Since there were many other patients with hepatocellular damage who had high H/L ratios similar to those in liver cirrhosis, the effect that hepatocellular damage has on the liver uptake of TI-201 is also considered. Our present data suggest that this noninvasive method seems to be useful in evaluating portal-to-systemic shunting.

Adult↗